Dial knob



Feb. 24, 192.

C. D. TUSKA DIAL KNOB Original Filed June 17, 1922 ENVENTOR ATTORNEYS 17% "the CUT.

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domination died June 11?, WW, ticriei Tito. sooner. Renewed December 1d, 19%.

e State of Connecticut, have invented new and useful improvements in Dial Knobs, of which the following is c specification.

This invention reietes to diai hnohs such as are used in connection with various kinds of radio and eiectricai apparatus tor adjust ing rotatahie parts thereof. i

The object of the invention is to provide certain new and usefui irnproveinentsin the construction oi molded diai hnohs tinniing to prevent warning and to secure tightness and strength with economy of manuiacture.

The invention consists in the improved diai imoh hereinafter descrihed end cioiinedi in the drawings,

i is a front eievationai view of n diai imoh constructed in accordance with the present invention;

Fi :2 is at side eievationni view of the no inst; i

3 is n rear eievationai view thereof;

Fin. and

idig. 5 is a fragmentary sectionoi view token on the tines 5-5 oi Fig. 3.

Referring the drawings, the iiiustinted diai hnoh comprises a central imoh portion 6 and an integral died portion 7, the whoie being rnoided from suitahie dieiectric ma teriai. As shown, the inioh portion 6 is peripheraiiy hnuried as indicoted ct 8, and the dini portion 7 has the usual heveiied margin hearing a vernier 9 that is adapted to cooperote with a suitahie. (not shown) upon at stationery port of the an paretus.

EDioi hnohsof this general character, as heretofore constructed have heen iiehie to warp more or iess ,with ego hy reason of the unequei distribution of the mess of material of which they are composed, the warping rcsuiting in iaterai distortion of the diet ig. d is c section taken on the line 4-4 or the recessed construction,

is indicated at it in Figs" 3 and i and is in the form oi an annular channel concentric with the axis of the knob. The shove described recessed construction provides a trensverse weh intermediate the front end rear faces of the diedknob and a central huh 16 which projects rearwardiy from the wehio to a piano flush with the rear face of the diai hnoh. The huh id is pro vided with an axial cyiindricai recess or here 18 for receiving the shaft or trunnion oi? the art to he rctatahiy adjusted, An internaiy screwthreaded bushing 26 {Fig i) many he anchored. in the central recess 18 to receive external screw-threads upon the shaft of the adjustahie port,

By reference to Fig. d widi he apparent that n practicciiy-uniicnn distrihution of the inoided mass is obtained by virtue oi the suhstontiaiiy sheietondike construction ati orded hr the arrangement of the recesses 12, it and 18. By constructing the diai touch in the improved manner shove described the ohjectionahic warping or distortion of the dial is nniteriaiigy reduced if not entirely eiiminated. The recessed construction also materially reduces the weight of the imoh and tends to iessen any possible capacity efiiect of the imoh upon the apporatus with which it is essociatcd, thus "losing a feature of some importance when the diai knot is used in connection with certein irinds of radio apparatus. Ohvioueiy n considerahie coring or materiel is effected by reason of Dial imohs, in common with other inoided articles oi? a siiniiar chnracter, are usuaiiy ejected from the die in which they are inoided by means of an ejector which is movable verticahy through the base of the die. Such ejectors engage the iowerinost face of the molded article during the molding operation and even though such an ejecting plunger is made flush with the hot tom of the naoid it inevitably makes a ark or scar on the moidod oiticie during the molding operation. in the cone of a dial oh, the front thee thereof? is lowermost in the mold and consequently it is this front face which is engaged by the ejector. Since the front face of the knob is exposed to view when the knob is in use it is particularly desirable that its surface should be finished smoothly and should be free from any disfiguring mark such as that produced by the ejector.

By shaping the mold so that the recess 12 is formed in the front face of the dial knob, it is practicable to make -the ejecting plunger of a diameter equal to that of the recess to be formed in the dial knob and to locate said plunger in the die so that its upper end will normally project into the die sufficiently to form the desired recess therein. Then when the ejecting plunger is subsequently elevated to eject the finished article from the mold it will raise said article by engagement throughout the entire area at the base of the recess in its lower face and as a result the finished surface of the article will not be marred or disfigured in any way. Furthermore, the provision of the recess 12 in the front face of the dial knob greatly improves the appearance of the article and thus renders it more readily salable.

It is often desirable to limit the range of rotation of the adjustable part to which the dial knob is attached. With this end in view, the present invention contemplates the, forming of one or more radial ribs or webs 22 across the annular recess 14 of the dial knob and the provision of a stop lug such as indicated at 23 in Fig. 4:, this lug projecting from a panel or other stationary part 24 and being adapted to extend into the recess 14 in. the dial knob in position to coact with the web or webs 22. The stop webs 22 are molded integrally with the rest of the dial knob and may be located in predeter mined positions to limit rotation of the dial to a desired number of degrees.

In certain combinations of radio apparatus where there are two or more parts to be rotatably adjusted by means of dial knobs it is desirable to limit in different degrees the movements of the several parts. In order that the ranges of rotational movements of different parts may be limited to different extents without the necessity of providing separate dial knobs in which the stop webs are arranged in different relative positions, the present invention contemplates the construction and arrangement of the stop webs 22 in such a manner that a single dial knob having at least two stop Webs is capable of being positioned relatively to the stop lug 23 so that either of two or more different ranges of rotational adjustment may be provided for as may be required. In the preferred form of the invention illustrated in the drawings, the stop webs 22 are positioned to divide the annular recess or channel 14 into a relatively short portion 25 and a relatively long portion 26. The arrangement and proportions of the webs 22 and of the stop lug 23 are such that when the dial knob is so located radially with respect to said stop lug that the latter projects into the short portion 25 of the channel 14, the range of rotational adjustment of the dial will be limited to 90 and when the dial knob is so located that the stop lug 23 projects into the long portion 26 of the channel 14:, the rangeof rotation of the dial will be limited to 180. Various ranges of rotation may be provided for by arranging stop webs in the recess 14 so as to provide arcuate channels of varying lengths which may be selectively arranged for cooperation with a single fixed stop lug. Obviously by this expedient dial knobs of identically the same design may be employed in connection with different adjustable parts to provide for different limits of rotational adjustment. The radial stop webs 22 also serve to stiffen and reinforce the dial knobs and thus render them less liable to breakage.

The invention having been described, what is claimed and desired to be secured by Letters Patent is- 1. A dial knob comprising a substantially cylindrical central knob portion and a peripheral dial portion disposed at right angles to the rotational axis of the dial knob, the whole being integrally formed of molded dielectric material and the opposite end faces of the knob being recessed to efiect a substantially uniform distribution of the mass of molded material.

2. A dial knob comprising a substantially cylindrical central knob portion and a peripheral dial portion disposed at right angles to the rotational axis of the dial knob, the whole being constructed of molded dielectric material and having a central recess in its rear face adapted to receive a shaft or like part and a deep annular channel concentric with said recess for securing a more nearly even distribution of the mass of material in the dial knob.

3. A dial knob for attachment to the shaft or trunnion of a rotatably adjustable element comprising integral knob and dial portions and having an annular channel in its rear face concentric with the periphery of the dial portion, and radial webs extending across said channel for coaqting with a fixed stop'to limit the range of rotation of the dia knob, said webs being relatively arranged to limit the rotation of the dial knob to one extent when the stop is operatively associated with the portion of the channel at one side of said webs and to limit said rotation to a dilferent extent when the stop is o eratively associated with the portion 0 the channel at the other side of said webs.

4. A dial knob for attachment to theshaft erci? or trunnion of a. rotatably adjustable element comprising integral knob and dial portions and having an annular channel in its rear face concentric with the periphery of the diel portion, and radial Webs extending across said channel for coacting with e fired stop to limit the range of rotation of the dial knob, said Webs dividing said channel into segments of dillerent lengths and being proportioned with respect to said stop to limit the rotation of the dial knob to 9. quarter turn whcn seid stop member is operutively ossociated with the shorter ent of the channel and to limit the rotation of the dial knob to o. half turn when said stop member is operetivelv associated with the longer segmented sci channel.

5. A diel knob comprising a substantially cylindricel central knob portion and o. periphersl dial portion disposed at right angles to the rotational axis of the dial lmob, the Whole being constructed of molded dielectric material and having it deep onnulor channel in its rear face and radial ribs extending ecross said channel for stidening end reinforcing the structure.

6. A dial knob comprising a substantially cylindrical central knob portion and a peripheral dial portion disposed at right angles to the rotational axis of the dial knob the whole being constructed of molded dielectric material and having a central recess in its rear face adapted to receive or shaft or like part, the knob having also an annular channel in its rear face concentric with said recess and aplurality of spaced apart strengthening ribs extending across said channel.

7. A dial knob comprising a substantially cylindrical central knob portion and a peripheral dial portion disposed at right angles to the rotational axis of the dial hob, the Whole being constructed of molded dielectric material and. having 8. control recess in its rear face adapted to receive or shaft or like part, an annular channel in sold rear face concentric with said recess, and stops in said channel for cooperating with e fixed stop to limit the rotation of the dial knob.

ln testimony whereof l hove efixed my signature.

CLARENCE D. TUSKA.

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